Cushing’s Disease

STEVE: Cushing’s disease usually occurs in older equines.

As a rule, it’s a secondary problem of the hypothalamus, and most
likely is due to a tumor. What ends up happening in cushingnoid horses, is
they release a ton more, or stimulate the adrenal glands to release a lot
more corticosteroids, and metorala corticords they call it.

What this does, is it creates a tremendous imbalance and their
ability to metabolize steroids essentially. But the problem you have is
that the secondary symptoms are that they don’t have, because it effects
the hypothalamus, they do not regulate their hair growth anymore, because
of the photoperiod.

Typically horses will release their hair as the days get longer, they
grow more hair as the days get shorter. The way we see this is that we put
mares under light in order to kinda fool them to get them to come into
heat, and they’ll shed.

It’s pretty obvious, you know, you can have a horse in the middle of,
you know, the arctic region and essentially if you have them under light,
16 hour light a day they’ll be slick coated as they can be, because you’ve
overridden the, you know, the hypothalamus, the balance in their brain and
the problem you have is, Cushing’s syndrome essentially overrides that, so
they dont have the ability to recognize photoperiod anymore and they also
release a bunch of corticosteriods.

So they are predisposed to founder quite readily and we put them on
something that will help control this, or try to override it. But it is a
tremendous health issue in older horses that you’ve got to be aware of.

And it is, requires a diagnostic work up by a veterinarian in order
to determine that you have an older horse with Cushing’s syndrome, and
exactly how you’re gonna treat it in order to maximize their quality of
life and use from the point forward.

ALEX: What are some of the symptoms you’d see that might lead to a
horse that’s having Cushing’s?

STEVE: Typically the hair coat’s probably the most obvious that they
do ever shed out, you know, here it is, the middle of summer and you’ve got
a coat on him like he’s in the middle of winter and he looks like a billy
goat. That’s pretty much, you know, one of the first signs and then other
signs are that they would founder very easily for no reason, and there’d
be no calls of it. Those two things right there are the, kind like the
cardinal signs and then we see some other things that would calls that as
well that are a little bit more in depth, but those would be the two most
obvious.